The present invention relates generally to latches useful in providing controlled operation of a panel or hatch and, more particularly, to a latch operated by rotational movement of the latch mechanism.
Hatches are often used to provide controlled access to a compartment or other area. For example, hatches are used in the marine industry to provide an enclosed area which may be easily accessed through manipulation of a hatch door or similar panel. Such hatches are often relied upon to keep objects in the enclosed area until needed and/or to provide for the safe storage of such objects, free from environmental and other elements. In the marine industry, environmental elements from which protection is sought may include damaging solar rays, moisture (such as corrosive salt water spray), and/or movement, such as that associated with a marine vessel in movement over water.
One typical hatch design in common use today includes a hatch door or panel having a hinge mechanism disposed along one edge to facilitate controlled movement of the hatch door between an open and a closed position. Additionally, the typical hatch design generally employs a latch mechanism disposed along an edge of the hatch door or panel to allow the hatch to be maintained in the closed position.
One such hatch and latch arrangement is shown in commonly assigned U.S. Pat. Nos. 5,231,948 and 5,358,291, both entitled xe2x80x9cHatch with Improved Latch and Hinge Assembly,xe2x80x9d the disclosures of which are hereby incorporated herein by reference. The latch mechanism provided in the above referenced patents provides a linearly moving biased latch pawl which engages a frame or panel into which the hatch door is set to thereby provide a force to maintain the hatch in the closed position. This latch mechanism is sometimes referred to as a xe2x80x9cslam latchxe2x80x9d because of its ability to close and engage with the closing motion of the hatch door. The hatch and latch mechanisms of these embodiments are provided in plastics, such as may include ultra-violet light inhibitors or other protective additives, or other non-corrosive materials to provide a system adapted to withstand such environmental elements as sun and moisture.
Another latch mechanism often found on such hatch assemblies involves a rotatably mounted bolt to engage a frame or panel into which the hatch is mounted. Such a latch mechanism is sometimes referred to as a xe2x80x9cdog down latchxe2x80x9d because of its aggressive retention of the hatch in the closed position.
Directing attention to FIG. 1, hatch 100 is shown including latch 120 employing a typical prior art xe2x80x9cdog down latchxe2x80x9d embodiment. Specifically, hatch 100 includes hatch door 110 coupled to frame 130 by hinges 111. Disposed along an edge opposite that of hinges 111 is latch 120 including bolt 121 disposed to engage frame 130 when hatch door 110 is in a closed position and, therefore, maintain hatch 100 in the closed position. In order to allow the opening and closing of hatch door 110, bolt 121 is mounted on shaft 122 which is rotatably disposed through hatch door 110. D ring 123 may be gripped by a user of hatch 100 and, thereby, rotational force may be applied to shaft 122 to cause bolt 121 to engage or disengage frame 130 as desired.
In order to allow hatch 100 to be disposed on a deck, bulkhead, or other surface with as nearly a flush surface as possible, hatch door 110 may include recess 112 in which shaft 122 is disposed. However, in order to operate hatch 100, the user must pivot D ring 123 from within recess 112 in order to provide D ring 123 in a proper orientation to allow the user to provide sufficient rotational force to the latch. Thereafter, the user must pivot D ring 123 to return it to within recess 112 so as not to cause D ring 123 to extend beyond the surface of hatch door 110, such as might present a trip or snag hazard on a deck or bulkhead.
It should be appreciated that the visible portion of latch 120 when hatch 100 is closed includes only shaft 122 and D ring 123. Accordingly it is often not possible to determine when bolt 121 has engaged frame 130 as the appearance of shaft 122 and D ring 123 are substantially identical when bolt 121 has engaged frame 130 and when bolt 121 is disposed in an orientation 180xc2x0 from engaging frame 130. Accordingly, a user can often attempt to latch hatch 100 and later discover that the hatch is not in fact latched.
Although a xe2x80x9cdog downxe2x80x9d type latch typically provides sufficient retention of the hatch door against the frame or panel into which it is mounted to provide an adequate seal against water infiltration around the hatch door, the latch itself is an area of potential water infiltration. Specifically, as the shaft or attached mechanism must penetrate the surface of hatch door 110 in order to couple with bolt 121, and there must be sufficient clearance for rotation of the shaft, there is a space through which water may pass. Accordingly, prior art solutions have typically engaged an O ring, made of a rubber or other resilient material, disposed around a portion of the shaft to engage a shaft hole edge in the hatch door to discourage water infiltration. The O ring is often disposed in such a way as to have substantial continuous and/or unequal pressure applied from the surfaces of the hatch door and/or the shaft both during rotation of the latch and when the latch is at rest. This pressure can result in premature failure of the seal as the friction often causes the material of the O ring to wear away. Similarly, often the water being discouraged from infiltration carries with it abrasive particles, such as sand and/or salt brine, further accelerating the wearing away of the seal. Moreover, the design of the latch assembly typically results in this O ring providing substantially the only defense to water infiltration.
Although not illustrated in the embodiment of FIG. 1, hatch 100 may be provided with a locking mechanism to discourage unauthorized access to an area enclosed thereby. It is difficult to employ a keyed locking mechanism on the shaft providing the rotational movement of the bolt. Accordingly, such locking mechanisms are often disposed separately from the latch, such as a separate lock cylinder and bolt disposed along an edge of the hatch door. Such an embodiment allows operation of the latch assembly, and thus its disengagement with the frame, relying upon the bolt of the locking mechanism to prevent opening of the hatch. Such an arrangement generally does not provide the level of security available with actually locking the latch mechanism. Additionally, prior art mechanisms are generally provided utilizing metal components which are prone to deterioration, such as through corrosion and/or rust when used in a marine environment. The prior art locking mechanisms also provide additional areas of potential water infiltration.
Accordingly, a need exists in the art for a latch system adapted to provide secure closing of a hatch door, even in rough and jarring movement, and to inhibit moisture from entering the enclosed area. A need exists in the art for the latch system to provide positive indication to a user of its engaged or disengaged status. Additionally, a need in the art exists for such a latch system to provide a substantially flush surface without requiring an operator to manipulate portions thereof to achieve such a flush surface. Moreover, a need exists in the art for the latch system to resist deterioration due to environmental elements.
A further need exists in the art for a latch system providing locked access such that persons not authorized to access the enclosed area are discouraged from opening the hatch door. A need in the art exists for a latch locking mechanism to be resistant to degradation, such as through exposure to environmental elements.
These and other objects, features and technical advantages are achieved by a system and method which employs a rotatable latch mechanism which is provided integrally with a hatch door, panel, or other surface of an assembly to be retained. A preferred embodiment of the present invention utilizes a hatch door configured to include a latch cup in which a portion of a latch mechanism, referred to herein as a latch actuator, is received. According to the preferred embodiment, the latch actuator includes a portion that extends through the latch cup to the underside of the hatch door to thereby engage a latch bolt portion of the latch mechanism. Of course, alternative embodiments might provide a portion of a latch bolt that extends through the latch cup to engage a latch actuator or a separate shaft portion to extend through the cup and engage both a latch actuator and a latch bolt.
The preferred embodiment latch actuator provides a surface through which a user may apply force to operate the latch mechanism. Through rotational manipulation of the latch actuator, the latch bolt of the preferred embodiment may be rotated to engage/disengage a hatch frame or panel into which the hatch is disposed. Preferably, the latch mechanism of the present invention is provided with stops to limit rotational movement of the latch actuator and latch bolt. For example, a preferred embodiment provides a stop at 0xc2x0, i.e., latch engaged, and a stop at 90xc2x0, i.e., latch disengaged. Through reference to the latch actuator, a user may easily determine the status of the latch.
The shape of the preferred embodiment latch cup and the shape of the preferred embodiment latch actuator substantially correspond to thereby provide a nesting arrangement when assembled, thus minimizing openings through which water infiltration may occur. Additionally, the preferred embodiment latch actuator is sized and shaped so as to provide substantially flush surfaces with the hatch door when disposed in the latch cup. Moreover, the preferred embodiment latch cup and latch actuator are shaped so as to cooperatively provide a surface between which a seal may be disposed. Alternative embodiments of the present invention provide multiple such surfaces to thereby provide a plurality of seals and, thus, improve the water impermeability of the latch mechanism.
According to a preferred embodiment, the nesting of the latch actuator within the latch cup is with relaxed force when the latch is disengaged and substantially throughout movement of the latch bolt to the engaged position. Accordingly, the life of seals utilized by the preferred embodiment latch mechanism may be prolonged by reduced frictional wear and/or reduced degradation due to the presence of abrasive particles.
A preferred embodiment of the latch bolt of the present invention provides a tapered, or ramped, surface which engages a frame or panel to maintain the hatch in a closed position. Accordingly, the latch mechanism may be operated without undue force, and the relaxed force of the nesting of the latch actuator in the latch cup may be maintained, throughout much of latch movement range. However, as the tapered surface of the latch bolt is moved to its fully engaged position, the forces holding the hatch door against the frame or panel into which it is disposed increase, thereby providing an affirmative or xe2x80x9cdog downxe2x80x9d latching force as well as an aggressive hatch seal.
According to a preferred embodiment of the present invention, the hatch door and/or latch cup disposed thereon includes surfaces, such as may be provided by annular tabs provided about the periphery of the latch bolt, against which the latch bolt transfers closing pressure from a hatch frame, or other engaged surface, to the hatch door. Accordingly, the interface between the latch bolt and latch actuator is substantially relieved of the aforementioned affirmative latching force which is instead transferred directly from the latch bolt to the hatch door through these surfaces. However, preferred embodiments of the invention provide for a portion of the closing pressure transferred from the latch bolt, such as may be controlled by a gap or other attribute of the aforementioned annular tabs, to provide a sealing pressure to a component or components of the latch assembly. Preferred embodiments of the present invention are adapted to apply the aforementioned sealing pressure substantially equally across a sealing surface. Accordingly, the life of seals may be prolonged by the equal application of force thereon.
A preferred embodiment of the present invention provides a locking mechanism to discourage unauthorized access to an area enclosed by the hatch. Preferably the locking mechanism is provided on the latch actuator to discourage its unauthorized manipulation. According to a preferred embodiment, the locking mechanism is provided in such a way as to engage a surface of the latch cup to thereby prevent rotation of the latch actuator disposed therein. The preferred embodiment of the locking mechanism is disposed so as to be on the weather side of a seal disposed between surfaces of the latch actuator and the latch cup. Accordingly, inclusion of such a locking mechanism in this embodiment of the latch does not introduce water infiltration problems.
Preferred embodiments of the above described latch mechanism components are made of plastics, resins, and/or composite materials to thereby withstand environmental elements, such as solar rays, moisture (such as corrosive salt water spray), and/or movement, such as that associated with a marine vessel in movement over water.
Accordingly, a technical advantage of the present invention is that the latch system of the preferred embodiment is adapted to provide secure closing of a hatch door and to inhibit moisture from entering the enclosed area.
A further technical advantage of the present invention is provided in that the latch system provides positive indication to a user of its engaged or disengaged status.
A still further technical advantage of the present invention is that the latch system provides a substantially flush surface without requiring an operator to manipulate portions thereof to achieve such a flush surface.
A yet further technical advantage of the present invention is that the latch system is resist to deterioration due to environmental elements.
Another technical advantage of the present invention is provided in employing a latch locking mechanism which is resistant to degradation, such as through exposure to environmental elements.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention.